Detection device and detection method

Abstract

To provide a detection device capable of accurately detecting the occurrence of a droplet discharge failure from a nozzle even when an imaging unit of a relatively low frame rate is used.SOLUTION: An adjustment unit 58 of a detection device 2 adjusts, in an adjustment mode, an imaging timing of an imaging unit 36 to a specific imaging timing so that droplets can appear in a first subject region 42 when droplets appear in a second subject region 44 of a subject image 46 corresponding to one or more of a plurality of sets of frame data while droplets do not appear in the first subject region 42 of each of the subject images 46 respectively corresponding to the plurality of sets of frame data. The adjustment unit 58 discharges, in a detection mode, droplets from a nozzle 6 at a prescribed discharge timing, images the subject images 46 by the imaging unit 36 at a specific imaging timing, and detects the occurrence of a droplet discharging failure from the nozzle 6 on the basis of the subject images 46 imaged at the specific imaging timing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a detection device and a detection method for detecting whether or not there is a defect in ejection of droplets from a nozzle. [Background technology]

[0002] Droplet ejection devices that eject droplets from nozzles using an inkjet system are known. The application range of this type of droplet ejection device is not limited to printing devices that eject ink onto a recording medium to perform printing, but has also expanded to include, for example, medical devices that eject medicinal solutions and beauty devices that eject cosmetic serums. When using droplet ejection devices in such medical devices or beauty devices, it is important to maintain the droplet ejection state from the nozzles (e.g., the amount of droplets ejected per ejection) in a normal state in order to properly obtain the efficacy of the medicinal solutions, cosmetic serums, etc.

[0003] For this reason, a detection device has been proposed for detecting whether or not there is a defect in the discharge of droplets from a nozzle (see, for example, Patent Document 1). In conventional detection devices, a camera (image capturing unit) captures an image of a droplet in flight discharged from a nozzle, and detects whether or not there is a defect in the discharge of droplets from the nozzle based on the imaged shape of the droplet in flight. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-206624 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional detection devices described above, in order to accurately detect the shape of droplets in flight, a high-speed camera capable of capturing images at a relatively high frame rate (e.g., 1000 fps or more) is required, which creates the problem of the detection device becoming large in size.

[0006] The present invention aims to solve the above-mentioned problems, and its purpose is to provide a detection device and a detection method that can accurately detect whether or not there is a defect in the ejection of droplets from a nozzle, even when an imaging unit with a relatively low frame rate is used. [Means for solving the problem]

[0007] In order to achieve the above object, a detection device according to a first aspect of the present invention is a detection device for detecting whether or not there is a malfunction in the discharge of droplets from a nozzle, the detection device comprising: a receiving member disposed opposite the nozzle and configured to receive droplets discharged from the nozzle; an imaging unit configured to capture, as a single subject image, a first subject area for capturing droplets in flight between the nozzle and the receiving member when droplets are discharged from the nozzle toward the receiving member, and a second subject area for capturing droplets that have landed on the receiving member; and a control unit for controlling the nozzle and the imaging unit, the control unit executing a first mode for adjusting the imaging timing of the imaging unit, and a second mode for detecting whether or not there is a malfunction in the discharge of droplets from the nozzle, wherein in the first mode, the control unit (i) causes droplets to be discharged from the nozzle at a predetermined discharge timing, and (ii) controls the imaging unit to capture, as a single subject image, a first subject area for capturing droplets in flight between the nozzle and the receiving member and a second subject area for capturing droplets that have landed on the receiving member. The subject image is captured at a predetermined frame rate, and (ii) when droplets are reflected in the second subject area of ​​the subject image corresponding to one or more frame data among the captured frame data, and droplets are not reflected in the first subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the imaging timing of the imaging unit is adjusted to a specific imaging timing so that droplets are reflected in the first subject area of ​​the subject image corresponding to a specific frame data among the plurality of frame data, and in the second mode, (iii) droplets are ejected from the nozzle at the predetermined ejection timing, and the imaging unit is caused to capture the subject image at the specific imaging timing, and (iv) based on the subject image captured at the specific imaging timing, the presence or absence of defective droplet ejection from the nozzle is detected.

[0008] According to this aspect, in the first mode, when droplets are not captured in the first subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the control unit adjusts the image capture timing of the image capture unit to a specific image capture timing so that droplets are captured in the first subject area of ​​the subject image corresponding to the specific frame data. This makes it possible to easily adjust the image capture timing of the image capture unit to the specific image capture timing in the first mode, even when an image capture unit with a relatively low frame rate is used, and to accurately detect whether or not there is a droplet ejection defect from the nozzle in the second mode.

[0009] For example, in a detection device according to a second aspect of the present invention, in the first aspect, the nozzle has a plurality of ejection holes for ejecting droplets, and the control unit may be configured to, in the first mode, eject droplets from a first number of the plurality of ejection holes of the nozzle at the predetermined ejection timing, and to, in the second mode, eject droplets from a second number of the plurality of ejection holes of the nozzle, the second number being greater than the first number, at the predetermined ejection timing.

[0010] According to this aspect, it is possible to reduce the amount of droplets consumed to adjust the imaging timing of the imaging unit to a specific imaging timing in the first mode.

[0011] For example, the detection device according to the third aspect of the present invention may be configured in the second aspect such that the first number is one.

[0012] According to this aspect, it is possible to more effectively reduce the amount of droplets consumed to adjust the imaging timing of the imaging unit to a specific imaging timing in the first mode.

[0013] For example, in the detection device according to the fourth aspect of the present invention, in the third aspect, the control unit may be configured to, in the first mode, when a droplet is ejected from the one ejection hole of the nozzle at the predetermined ejection timing, if the droplet is not reflected in either the first subject area or the second subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, determine that one ejection hole is defective, change the ejection hole that ejects the droplet from that one ejection hole to another ejection hole, and execute the first mode again.

[0014] According to this aspect, if one ejection hole is determined to be defective in the first mode, the ejection hole that ejects droplets can be changed from that ejection hole to another ejection hole, thereby allowing the first mode to continue.

[0015] For example, in the detection device according to the fifth aspect of the present invention, in any one of the first to fourth aspects, the control unit may be configured to adjust the imaging timing of the imaging unit to the specific imaging timing by lengthening or shortening an imaging delay time from the start of imaging control by the imaging unit to the execution of imaging by a predetermined time when, in the first mode, a droplet is captured in the second subject area of ​​the subject image corresponding to one or more frame data among the plurality of frame data, and a droplet is not captured in the first subject area of ​​each of the plurality of subject images corresponding to each of the plurality of frame data.

[0016] According to this aspect, the imaging timing of the imaging unit can be easily adjusted to a specific imaging timing.

[0017] For example, in the detection device according to the sixth aspect of the present invention, in the fifth aspect, the predetermined time is 2 times the reciprocal of the frame rate. n Alternatively, the value may be set to 1 / (n is an integer of 1 or more).

[0018] According to this aspect, the image capturing timing of the image capturing unit can be more easily and effectively adjusted to a specific image capturing timing.

[0019] For example, in a detection device according to a seventh aspect of the present invention, in any one of the first to sixth aspects, the receiving member is an endless belt having a receiving surface that receives droplets ejected from the nozzle, and the detection device may further be configured to include a drive source for rotating the receiving member in a predetermined direction, and a cleaning member that is arranged to contact the receiving surface of the receiving member and wipes off droplets that have landed on the receiving surface of the receiving member while the receiving member is rotating in the predetermined direction.

[0020] According to this aspect, by using a cleaning member to wipe off droplets that have landed on the receiving surface of the receiving member, the droplets that have landed and are reflected in the second subject area can be accurately analyzed by image processing each time the first mode is executed.

[0021] For example, in the detection device according to the eighth aspect of the present invention, in any one of the first to seventh aspects, the detection device may further include a mirror for reflecting droplets that have landed on the receiving member, and the second subject area may be configured to be an area that includes the mirror.

[0022] According to this aspect, the degree of freedom in arranging the receiving member can be increased.

[0023] A detection method according to a ninth aspect of the present invention is a detection method for detecting whether or not there is a defective discharge of droplets from a nozzle, and includes the steps of: (a) when droplets are discharged from the nozzle toward a receiving member arranged opposite the nozzle, using an imaging unit to capture, as a single subject image, a first subject area for capturing droplets in flight between the nozzle and the receiving member and a second subject area for capturing droplets that have landed on the receiving member; (b) executing a first mode for adjusting the imaging timing of the imaging unit; and (c) executing a second mode for detecting whether or not there is a defective discharge of droplets from the nozzle, wherein in the first mode, (i) droplets are discharged from the nozzle at a predetermined discharge timing, and the subject image is captured by the imaging unit at a predetermined frame rate. (ii) when droplets are reflected in the second subject area of ​​the subject image corresponding to one or more frame data among the captured frame data, and droplets are not reflected in the first subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the imaging timing of the imaging unit is adjusted to a specific imaging timing so that droplets are reflected in the first subject area of ​​the subject image corresponding to a specific frame data among the plurality of frame data, and in the second mode, (iii) droplets are ejected from the nozzle at the specified ejection timing, and the subject image is captured by the imaging unit at the specific imaging timing, and (iv) whether or not there is a defective ejection of droplets from the nozzle is detected based on the subject image captured at the specific imaging timing.

[0024] According to this aspect, in the first mode, when droplets are not captured in the first subject area of ​​each of a plurality of subject images corresponding to a plurality of frame data, the imaging timing of the imaging unit is adjusted to a specific imaging timing so that droplets are captured in the first subject area of ​​the subject image corresponding to a specific frame data. As a result, even when an imaging unit with a relatively low frame rate is used, the imaging timing of the imaging unit can be easily adjusted to the specific imaging timing in the first mode, and the presence or absence of defective droplet ejection from the nozzle can be accurately detected in the second mode. [Effects of the Invention]

[0025] According to the detection device and the like according to one aspect of the present invention, even when an imaging unit with a relatively low frame rate is used, it is possible to accurately detect whether or not there is a defective discharge of droplets from a nozzle. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view showing the appearance of a detection device according to a first embodiment. [Figure 2] 1 is a perspective view showing the appearance of the detection device according to the first embodiment with the cartridge removed. FIG. [Figure 3] FIG. 2 is a diagram showing the nozzles of the cartridge. [Figure 4] FIG. 2 is a perspective view showing the internal structure of the detection device according to the first embodiment. [Figure 5] 5 is a perspective view showing the internal structure of the detection device according to the first embodiment, as seen from an angle different from that of FIG. 4. FIG. [Figure 6] 3 is a diagram showing an example of a subject image captured by an imaging unit of the detection device according to the first embodiment. FIG. [Figure 7] 1 is a block diagram showing a functional configuration of a detection device according to a first embodiment. [Figure 8] 4 is a flowchart showing the flow of operations of the detection device according to the first embodiment. [Figure 9] 4 is a timing chart for explaining the operation in the adjustment mode (first time of adjusting the imaging timing) of the detection device according to the first embodiment. [Figure 10] 9 is a flowchart specifically showing the content of step S16 in the flowchart of FIG. 8. [Figure 11] 10 is a timing chart for explaining the operation in the adjustment mode (second adjustment of imaging timing) of the detection device according to the first embodiment. [Figure 12]10 is a timing chart for explaining the operation in the adjustment mode (third adjustment of imaging timing) of the detection device according to the first embodiment. [Figure 13] 10 is a timing chart for explaining the operation in the adjustment mode (fourth adjustment of imaging timing) of the detection device according to the first embodiment. [Figure 14] 4 is a timing chart for explaining the operation of the detection device according to the first embodiment in a detection mode. [Figure 15] 5A and 5B are diagrams for explaining the operation of the detection device according to the first embodiment in a detection mode. [Figure 16] FIG. 10 is a perspective view showing the internal structure of a detection device according to a second embodiment. [Figure 17] FIG. 11 is a perspective view showing the appearance of a detection device according to a third embodiment. [Figure 18] FIG. 11 is a perspective view showing the appearance of a detection device according to a third embodiment with a cartridge removed. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement positions, and connection forms shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0028] (Embodiment 1) [1-1. Structure of the detection device] First, the structure of the detection device 2 according to the first embodiment will be described with reference to FIGS. 1 to 6. FIG. 1 is a perspective view showing the appearance of the detection device 2 according to the first embodiment. FIG. 2 is a perspective view showing the appearance of the detection device 2 according to the first embodiment with the cartridge 4 removed. FIG. 3 is a diagram showing the nozzle 6 of the cartridge 4. FIG. 4 is a perspective view showing the internal structure of the detection device 2 according to the first embodiment. FIG. 5 is a perspective view showing the internal structure of the detection device 2 according to the first embodiment as viewed from an angle different from that of FIG. 4. FIG. 6 is a diagram showing an example of a subject image 46 captured by the imaging unit 36 ​​of the detection device 2 according to the first embodiment.

[0029] 1 to 5, the front-to-rear direction of the detection device 2 is the X-axis, the left-to-right direction of the detection device 2 is the Y-axis, and the up-to-down direction of the detection device 2 is the Z-axis. The positive side of the Z-axis is "up" and the negative side of the Z-axis is "down."

[0030] As shown in FIGS. 1 and 2, the detection device 2 is a device for detecting whether or not there is a failure in ejecting droplets from the nozzles 6 of the cartridge 4 (see FIG. 3).

[0031] The cartridge 4 is detachably attached to a droplet ejection device (not shown) for ejecting a mist of liquid (droplets) using, for example, an inkjet system. The liquid is, for example, a solution such as a medicinal solution or a beauty serum. The droplet ejection device is, for example, a small, handheld device such as a medical device for ejecting a medicinal solution or a beauty device for ejecting a beauty serum. Such a small device is used by, for example, holding it in one hand of a user.

[0032] A receiving section 8, which is a terminal for receiving a discharge control signal from outside the cartridge 4, is disposed on the side of the cartridge 4. A storage section 10 for filling with solution is formed inside the cartridge 4. Since the cartridge 4 is to be mounted in a small device, the size of the cartridge 4 is made small, and accordingly the volume of the storage section 10 is smaller than the volume of the storage section of an ink cartridge for a general printing device.

[0033] 3, a nozzle 6 is disposed on the bottom surface of the cartridge 4 for discharging the solution supplied from the storage unit 10 downward as droplets based on a discharge control signal received by the receiving unit 8. The nozzle 6 has a plurality of (e.g., seven) minute discharge holes 12 formed therein. The plurality of discharge holes 12 are arranged in a line at intervals along the front-to-rear direction (X-axis direction).

[0034] The detection device 2 includes a housing 14. A slot 16 is formed on the top surface of the housing 14 for detachably inserting the cartridge 4. When detecting whether there is a problem with the ejection of droplets from the nozzle 6 of the cartridge 4, the user inserts the cartridge 4 into the slot 16 of the housing 14 from above with the nozzle 6 facing downward.

[0035] 4 and 5, the detection device 2 further includes a detection mechanism 18 disposed inside the housing 14. The detection mechanism 18 includes a control board 20, a transmitter 22, a drive pulley 24, a driven pulley 26, a receiving member 28, a drive source 30, a cleaning member 32, a light source 34, and an imaging unit 36. Although FIGS. 4 and 5 show a state in which the cartridge 4 is inserted into the slot 16 of the housing 14, for convenience of explanation, the housing 14 is not shown.

[0036] The control board 20 is a printed circuit board for controlling the nozzles 6 and the imaging unit 36, and generates, for example, a discharge control signal and an imaging control signal. The control board 20 also executes an adjustment mode (an example of a first mode) for adjusting the imaging timing of the imaging unit 36, and a detection mode (an example of a second mode) for detecting whether or not there is a discharge defect in droplets from the nozzles 6. Specific details of the adjustment mode and the detection mode will be described later.

[0037] The transmitter 22 is a terminal for transmitting the ejection control signal generated by the control board 20, and is mounted on the control board 20. As shown in FIG. 4 , when the cartridge 4 is inserted into the slot 16 of the housing 14, the transmitter 22 is electrically connected to the receiver 8 of the cartridge 4. In this state, the transmitter 22 transmits the ejection control signal generated by the control board 20 to the receiver 8 of the cartridge 4.

[0038] The drive pulley 24 and the driven pulley 26 are each rotatably supported inside the housing 14 and extend in the front-to-rear direction. The drive pulley 24 and the driven pulley 26 are also arranged at an interval in a direction inclined with respect to the up-down direction (Z-axis direction).

[0039] The receiving member 28 is, for example, an endless belt, and is rotatably wound around the drive pulley 24 and the driven pulley 26. The receiving member 28 is disposed opposite the nozzle 6 of the cartridge 4. A receiving surface 38 is defined on the outer circumferential surface of the receiving member 28. The receiving surface 38 of the receiving member 28 is disposed at an angle with respect to the horizontal plane (XY plane), and receives droplets ejected from the nozzle 6. In other words, the droplets ejected from the nozzle 6 fly (fall) between the nozzle 6 and the receiving surface 38 of the receiving member 28, and then land (adhere) on the receiving surface 38 of the receiving member 28.

[0040] The drive source 30 is, for example, a servo motor, and is connected to one end of the drive pulley 24. When the drive force of the drive source 30 is transmitted to the drive pulley 24, the drive pulley 24 rotates, and accordingly the receiving member 28 rotates in a predetermined direction. The drive of the drive source 30 is controlled by the control board 20.

[0041] The cleaning member 32 is a wiper blade made of, for example, rubber. It is disposed on the opposite side of the receiving member 28 from the nozzle 6, and is disposed so as to come into contact with the receiving surface 38 of the receiving member 28. The cleaning member 32 wipes away droplets that have landed on the receiving surface 38 of the receiving member 28 while the receiving member 28 is rotating in a predetermined direction.

[0042] The light source 34 is a light source for illuminating the imaging area of ​​the imaging unit 36. The light source 34 is, for example, a light emitting diode that emits white light, and is disposed to the side of the receiving surface 38 of the receiving member 28.

[0043] The imaging unit 36 ​​is a camera that captures images at a relatively low predetermined frame rate (e.g., 30 fps). The imaging unit 36 ​​is disposed to the side of the receiving surface 38 of the receiving member 28, and is mounted on the control board 20 via a flexible substrate 40. As shown in FIG. 6 , when droplets are ejected from the nozzle 6 of the cartridge 4 toward the receiving surface 38 of the receiving member 28, the imaging unit 36 ​​captures, as one subject image 46, a first subject area 42 for capturing the droplets flying between the nozzle 6 and the receiving surface 38, and a second subject area 44 for capturing the droplets that have landed on the receiving surface 38. The vertical size of the imaging area of ​​the imaging unit 36 ​​is, for example, approximately 16 mm.

[0044] The imaging unit 36 ​​receives an imaging control signal from the control board 20 via the flexible board 40, thereby capturing a plurality of subject images 46 at a predetermined frame rate. The imaging unit 36 ​​also transmits a plurality of frame data corresponding to each of the plurality of subject images 46 captured at the predetermined frame rate to the control board 20 via the flexible board 40. Specifically, the imaging unit 36 ​​generates frame data, which is image data representing the captured subject image 46, every time it captures a subject image 46 at a time interval that is the reciprocal of the predetermined frame rate (1 / 30≈33 ms), and sequentially transmits the generated plurality of frame data to the control board 20.

[0045] [1-2. Functional configuration of the detection device] Next, the functional configuration of the detection device 2 according to the first embodiment will be described with reference to Fig. 7. Fig. 7 is a block diagram showing the functional configuration of the detection device 2 according to the first embodiment.

[0046] As shown in FIG. 7, the detection device 2 includes an imaging unit 36, a storage unit 48, and a control unit 50 as functional components.

[0047] The imaging unit 36 ​​captures a plurality of subject images 46 (see FIG. 6) at a predetermined frame rate based on an imaging control signal from an imaging control unit 54 (described later). The imaging unit 36 ​​sequentially stores in the storage unit 48 a plurality of frame data corresponding to the plurality of subject images 46 captured at the predetermined frame rate.

[0048] The storage unit 48 is a RAM (Random Access Memory) for storing a plurality of frames of data from the imaging unit 36. The storage unit 48 is realized by the control board 20 described above (see FIG. 4).

[0049] The control unit 50 includes a discharge control unit 52, an imaging control unit 54, an analysis unit 56, and an adjustment unit 58. The control unit 50 is realized by the control board 20 described above.

[0050] The ejection control unit 52 controls the ejection of droplets from the nozzles 6 of the cartridge 4. Specifically, the ejection control unit 52 generates an ejection control signal based on an instruction from the adjustment unit 58, and transmits the generated ejection control signal to the receiving unit 8 of the cartridge 4 (see FIG. 4). The ejection control signal is a signal for controlling the nozzle 6 so that droplets of a predetermined amount (for example, 10 pL per ejection hole 12) are ejected from one or more of the multiple ejection holes 12 of the nozzle 6 at a predetermined ejection timing. Here, the predetermined ejection timing is the timing at which droplets are actually ejected from the nozzle 6 after an ejection delay time (hereinafter also referred to as "ejection delay") has elapsed since the ejection control unit 52 started to control the ejection of droplets.

[0051] The imaging control unit 54 controls the imaging of the subject images 46 by the imaging unit 36. Specifically, the imaging control unit 54 generates an imaging control signal based on an instruction from the adjustment unit 58, and transmits the generated imaging control signal to the imaging unit 36. The imaging control signal is a signal for controlling the imaging unit 36 ​​to capture a plurality of subject images 46 at a predetermined frame rate.

[0052] The analysis unit 56 sequentially acquires a plurality of frame data from the storage unit 48, and analyzes by image processing whether or not droplets are reflected in the first subject region 42 or the second subject region 44 of each of a plurality of subject images 46 corresponding to the acquired plurality of frame data. The analysis unit 56 notifies the adjustment unit 58 of the analysis result.

[0053] Based on the analysis result from the analysis unit 56, the adjustment unit 58 instructs the discharge control unit 52 to generate a discharge control signal, and instructs the imaging control unit 54 to generate an imaging control signal. Specifically, in the adjustment mode, the adjustment unit 58 controls the imaging control unit 54 to adjust the imaging timing of the imaging unit 36 ​​as described below. Here, the imaging timing refers to the timing at which the imaging unit 36 ​​actually captures the subject image 46 after an imaging delay time (hereinafter also referred to as "imaging delay") has elapsed since the imaging control unit 54 started controlling imaging.

[0054] [1-3. Operation of the detection device] [1-3-1. Adjustment mode operation] The operation of the detection device 2 according to the first embodiment in the adjustment mode will be described with reference to FIGS. 8 to 13. FIG. 8 is a flowchart showing the flow of the operation of the detection device 2 according to the first embodiment. FIG. 9 is a timing chart for explaining the operation of the detection device 2 according to the first embodiment in the adjustment mode (first adjustment of the imaging timing). FIG. 10 is a flowchart specifically showing the content of step S16 in the flowchart of FIG. 8. FIG. 11 is a timing chart for explaining the operation of the detection device 2 according to the first embodiment in the adjustment mode (second adjustment of the imaging timing). FIG. 12 is a timing chart for explaining the operation of the detection device 2 according to the first embodiment in the adjustment mode (third adjustment of the imaging timing). FIG. 13 is a timing chart for explaining the operation of the detection device 2 according to the first embodiment in the adjustment mode (fourth adjustment of the imaging timing).

[0055] As shown in FIG. 8 , the control unit 50 first sets the initial values ​​of the following parameters (S11). Specifically, the control unit 50 sets the initial values ​​of the parameters as follows: (a) the initial value of the mode to be executed, “adjustment mode”; (b) the initial value of the ejection hole 12 to be ejected from among the multiple ejection holes 12 of the nozzle 6, “one ejection hole 12”; (c) the initial value of the ejection delay time, “250 ms”; (d) the initial value of the image capture delay time, “100 ms”; (e) the initial value of the predetermined frame rate of the image capture unit 36, “30 fps”; and (f) the initial value of the number of times the adjustment mode will be executed, “0 times.” Note that the initial values ​​listed above are merely examples, and any initial value other than the above may be set. By setting the initial values ​​of the parameters in this manner, the adjustment mode is first executed as follows.

[0056] Next, the adjustment unit 58 instructs the discharge control unit 52 to generate a discharge control signal, and instructs the imaging control unit 54 to generate an imaging control signal. Next, the discharge control unit 52 generates a discharge control signal based on the instruction from the adjustment unit 58, and transmits the generated discharge control signal to the receiving unit 8 of the cartridge 4. Furthermore, the imaging control unit 54 generates an imaging control signal based on the instruction from the adjustment unit 58, and transmits the generated imaging control signal to the imaging unit 36.

[0057] This causes the nozzles 6 of the cartridge 4 to start ejecting droplets, and also causes the imaging unit 36 ​​to start capturing an image of the subject 46 (S12). This causes the first adjustment of the imaging timing in the adjustment mode to be performed, as shown in Fig. 9. It should be noted that, as shown in Fig. 9(a) and (b), the timing at which control of droplet ejection from the nozzles 6 starts and the timing at which control of imaging by the imaging unit 36 ​​starts are assumed to be the same.

[0058] 9(a), after a discharge delay time of 250 ms has elapsed since the start of droplet discharge control by the discharge control unit 52, a predetermined amount of droplets is discharged from one discharge hole 12 (an example of the first number) of the nozzles 6. Here, the discharge period from the start to the end of discharge of the predetermined amount of droplets from one discharge hole 12 of the nozzle 6 (i.e., the period during which the predetermined amount of droplets discharged from one discharge hole 12 are flying) is, for example, about 3 ms.

[0059] 9(b), after an imaging delay time of 100 ms has elapsed since the start of imaging control by the imaging control unit 54, the imaging unit 36 ​​captures a plurality of subject images 46 at a predetermined frame rate. If the imaging timing of the imaging unit 36 ​​is included within the above-mentioned discharge period (3 ms), a flying droplet will be reflected in the first subject region 42 of the subject image 46 corresponding to the specific frame data captured by the imaging unit 36. Note that, in the first adjustment of the imaging timing shown in FIG. 9, the imaging timing of the imaging unit 36 ​​is not included within the above-mentioned discharge period.

[0060] 9(c), the imaging unit 36 ​​sequentially stores in the storage unit 48 a plurality of frame data corresponding to a plurality of subject images 46 captured at a predetermined frame rate. At this time, the plurality of frame data stored in the storage unit 48 are assigned frame numbers, such as "frame 1," "frame 2," "frame 3," "frame 4," ..., "frame n" (n is an integer equal to or greater than 2), in the order of capture. That is, the frame data captured first is assigned the frame number "frame 1," and the frame data captured last is assigned the frame number "frame n." For convenience of explanation, the following description will only cover the frame data with frame numbers "frame 1" to "frame 4."

[0061] If the ejection of droplets from the nozzle 6 of the cartridge 4 and the capture of the subject image 46 by the imaging unit 36 ​​have not been completed (NO in S13), the process returns to step S13. If the ejection of droplets from the nozzle 6 of the cartridge 4 and the capture of the subject image 46 by the imaging unit 36 ​​have been completed (YES in S13), the analysis unit 56 sequentially acquires multiple frame data from the storage unit 48 (S14). Next, in adjustment mode ("adjustment mode" in S15), the imaging timing of the imaging unit 36 ​​is adjusted (S16).

[0062] Here, the content of step S16 in the flowchart of FIG. 8 will be specifically described with reference to FIGS.

[0063] As shown in (a) to (c) of Figure 9, when the imaging timing is adjusted for the first time in the adjustment mode, the imaging timing of the imaging unit 36 ​​is not included in the above-mentioned ejection period, and the droplets after landing are reflected in the second subject area 44 of each of the multiple subject images 46 corresponding to the multiple frame data of frame numbers "frame 3" and "frame 4", respectively, and the droplets in flight are not reflected in the first subject area 42 of each of the multiple subject images 46 corresponding to the multiple frame data of frame numbers "frame 1" to "frame 4".

[0064] As shown in FIG. 10, first, the analysis unit 56 detects whether or not a flying droplet is reflected in the first subject area 42 of the subject image 46 corresponding to the frame data with frame number "frame 1" (S1601).

[0065] If the first subject area 42 of the subject image 46 corresponding to the frame data with frame number "Frame 1" does not show a flying droplet (NO in S1601), the analysis unit 56 detects whether the second subject area 44 of the subject image 46 corresponding to the frame data with frame number "Frame 1" shows a droplet after landing (S1602).

[0066] If the second subject area 44 of the subject image 46 corresponding to the frame data of frame number "frame 1" does not show any droplets after landing (NO in S1602), the analysis unit 56 determines whether the frame data of frame number "frame 1" is the last frame data (S1603). If the frame data of frame number "frame 1" is not the last frame data (NO in S1603), the analysis unit 56 starts analyzing the frame data of the next frame number "frame 2" (S1604), and returns to step S1601.

[0067] On the other hand, in step S1603, if the analyzed frame data is the last frame data (YES in S1603), then no droplets are reflected in the first subject region 42 or the second subject region 44 of the subject image 46 corresponding to the frame data of either frame number. Therefore, in this case, the analysis unit 56 determines that one of the ejection holes 12 of the nozzle 6 is defective, changes the ejection hole that ejects droplets from that one ejection hole 12 to another ejection hole 12, and executes the adjustment mode again (S1605).

[0068] Returning to step S1602, if the second subject area 44 of the subject image 46 corresponding to the frame data with frame number "frame 3" shows a droplet after landing (YES in S1602), the analysis unit 56 determines whether or not the image capturing timing has been adjusted for the first time (S1606). If the image capturing timing has been adjusted for the first time (YES in S1606), the analysis unit 56 saves the frame number "frame 3" of the frame data in which the droplet after landing was first shown (S1607).

[0069] Next, the adjustment unit 58 determines whether the frame number of the frame data in which the droplet first appears after landing in this adjustment of the imaging timing is greater than the frame number "frame 3" (i.e., the step number saved in step S1607) of the frame data in which the droplet first appears after landing in the initial adjustment of the imaging timing (S1608).

[0070] In the current adjustment of the imaging timing, if the frame number of the frame data in which the droplet first appears after landing is equal to "frame 3" (NO in S1608), the adjustment unit 58 adjusts the imaging timing of the imaging unit 36 ​​to be earlier (S1609). Specifically, the adjustment unit 58 adjusts the imaging delay time of 100 ms to 2 times the reciprocal of the frame rate (33 ms). 1 The image capturing timing of the image capturing unit 36 ​​is adjusted by shortening the image capturing timing by 16 ms (≈ 33 ms × ½) (an example of the predetermined time) to 84 ms (= 100 ms - 16 ms). Thereafter, the process returns to step S1601, and the second adjustment of the image capturing timing in the adjustment mode is performed. That is, the adjustment of the image capturing timing in the adjustment mode is repeatedly performed as described below until the image capturing timing of the image capturing unit 36 ​​is included within the above-mentioned discharge period.

[0071] In addition, in the above-mentioned step S1609, if the frame number of the frame data in which the droplet first appears after impact in the current adjustment of the imaging timing is equal to "frame 3," the adjustment unit 58 may adjust the imaging timing in the direction of delaying it by lengthening the imaging delay time by a predetermined time.

[0072] Following the first adjustment of the imaging timing in the adjustment mode, a second adjustment of the imaging timing in the adjustment mode is performed, as shown in Fig. 11. As shown in Fig. 11(a), a predetermined amount of droplets is ejected from one of the ejection holes 12 of the nozzle 6 at a timing when an ejection delay time of 250 ms has elapsed since the ejection control unit 52 started controlling droplet ejection. Also, as shown in Fig. 11(b), at a timing when an imaging delay time of 84 ms (i.e., the imaging delay time adjusted in the first adjustment of the imaging timing in the adjustment mode) has elapsed since the imaging control unit 54 started controlling imaging, the imaging unit 36 ​​captures a plurality of subject images 46 at a predetermined frame rate. Also, as shown in Fig. 11(c), the imaging unit 36 ​​sequentially stores a plurality of frame data corresponding to the plurality of subject images 46 captured at the predetermined frame rate in the storage unit 48.

[0073] As shown in (a) to (c) of Figure 11, in the second adjustment of the imaging timing in the adjustment mode, the imaging timing of the imaging unit 36 ​​is not included in the above-mentioned ejection period, and the droplets after landing are reflected in the second subject area 44 of each of the multiple subject images 46 corresponding to the multiple frame data of frame numbers "frame 3" and "frame 4", respectively, and the droplets in flight are not reflected in the first subject area 42 of each of the multiple subject images 46 corresponding to the multiple frame data of frame numbers "frame 1" to "frame 4".

[0074] In the second image capture timing adjustment in the adjustment mode, steps S1601 to S1605 are first executed as described above. In step S1602, if a droplet after landing is reflected in second object region 44 of object image 46 corresponding to frame data with frame number "frame 3" (YES in S1602), proceed to step S1606. If this is not the first time the image capture timing is adjusted (NO in S1606), proceed to step S1608.

[0075] In this adjustment of the imaging timing, if the frame number of the frame data in which the droplet first appears after landing is equal to "frame 3" (NO in S1068), the adjustment unit 58 adjusts the imaging timing to be earlier (S1609). Specifically, the adjustment unit 58 adjusts the imaging delay time of 84 ms to 2 times the reciprocal of the frame rate (33 ms). 2 The imaging timing of the imaging unit 36 ​​is adjusted by shortening the predetermined time by 8 ms (≈33 ms × ¼) (an example of a predetermined time) to 76 ms (=84 ms - 8 ms). Then, the process returns to step S1601, and the third adjustment of the imaging timing in the adjustment mode is executed.

[0076] Following the second adjustment of the imaging timing in the adjustment mode, a third adjustment of the imaging timing in the adjustment mode is performed, as shown in Fig. 12. As shown in Fig. 12(a), a predetermined amount of droplets is ejected from one of the ejection holes 12 of the nozzle 6 at a timing when an ejection delay time of 250 ms has elapsed since the ejection control unit 52 started controlling the droplet ejection. Also, as shown in Fig. 12(b), at a timing when an image capture delay time of 76 ms (i.e., the image capture delay time adjusted in the second adjustment of the imaging timing in the adjustment mode) has elapsed since the image capture control unit 54 started controlling the image capture, the image capture unit 36 ​​captures a plurality of subject images 46 at a predetermined frame rate. Also, as shown in Fig. 12(c), the image capture unit 36 ​​sequentially stores a plurality of frame data corresponding to the plurality of subject images 46 captured at the predetermined frame rate in the storage unit 48.

[0077] As shown in (a) to (c) of Figure 12, in the third adjustment of the imaging timing in the adjustment mode, the imaging timing of the imaging unit 36 ​​is not included within the above-mentioned ejection period, and the droplet after landing is reflected in the second subject area 44 of the subject image 46 corresponding to the frame data of frame number "frame 4", and the droplet in flight is not reflected in each of the first subject areas 42 of the multiple subject images 46 corresponding to the multiple frame data of frame numbers "frame 1" to "frame 4".

[0078] In the third image capture timing adjustment in the adjustment mode, steps S1601 to S1605 are first executed as described above. In step S1602, if a droplet after landing is reflected in second object region 44 of object image 46 corresponding to frame data with frame number "frame 4" (YES in S1602), proceed to step S1606. If this is not the first time the image capture timing is adjusted (NO in S1606), proceed to step S1608.

[0079] In this adjustment of the imaging timing, if the frame number "frame 4" of the frame data in which the droplet first appears after landing is greater than "frame 3" (YES in S1068), the adjustment unit 58 adjusts the imaging timing to delay it (S1610). Specifically, the adjustment unit 58 adjusts the imaging delay time of 76 ms to 2 times the reciprocal of the frame rate (33 ms). 3 The imaging timing of the imaging unit 36 ​​is adjusted by lengthening the predetermined time by 4 ms (≈33 ms × ⅛) (an example of a predetermined time) to 80 ms (=76 ms + 4 ms). Then, the process returns to step S1601, and the fourth adjustment of the imaging timing in the adjustment mode is executed.

[0080] In addition, in the above-mentioned step S1610, if the frame number "frame 4" of the frame data in which the droplet first appears after impact during the current adjustment of the imaging timing is greater than "frame 3," the adjustment unit 58 may adjust the imaging timing to be earlier by shortening the imaging delay time by a predetermined time.

[0081] Following the third adjustment of the imaging timing in the adjustment mode, a fourth adjustment of the imaging timing in the adjustment mode is performed, as shown in Fig. 13. As shown in (a) of Fig. 13, a predetermined amount of droplets is ejected from one of the ejection holes 12 of the nozzle 6 at a timing when an ejection delay time of 250 ms has elapsed since the ejection control unit 52 started controlling the droplet ejection. Also, as shown in (b) of Fig. 13, at a timing when an image capture delay time of 80 ms (i.e., the image capture delay time adjusted in the third adjustment of the imaging timing in the adjustment mode) has elapsed since the image capture control unit 54 started controlling the image capture, the image capture unit 36 ​​captures a plurality of subject images 46 at a predetermined frame rate. Also, as shown in (c) of Fig. 13, the image capture unit 36 ​​sequentially stores a plurality of frame data representing the plurality of subject images 46 captured at the predetermined frame rate in the storage unit 48.

[0082] As shown in (a) to (c) of Figure 13, in the fourth adjustment of the imaging timing in the adjustment mode, the imaging timing of the imaging unit 36 ​​is included within the above-mentioned ejection period, and the droplet after landing is reflected in the second subject area 44 of the subject image 46 corresponding to the frame data of frame number "frame 4", and the droplet in flight is reflected in the first subject area 42 of the subject image 46 corresponding to the frame data of frame number "frame 3".

[0083] In the fourth adjustment of the imaging timing in the adjustment mode, if, in step S1601, a flying droplet is captured in the first subject area 42 of the subject image 46 corresponding to the frame data with frame number "frame 3" (YES in S1601), the analysis unit 56 saves the frame number "frame 3" of the frame data in which the flying droplet is captured (S1611).

[0084] That is, in this case, the adjustment unit 58 adjusts the imaging timing of the imaging unit 36 ​​to a specific imaging timing during the third adjustment of the imaging timing in the adjustment mode so that a flying droplet is captured in the first subject area 42 of the subject image 46 corresponding to the frame data with frame number "frame 3." Here, the specific imaging timing is the imaging timing at which the imaging unit 36 ​​captures the subject image 46 within the above-mentioned discharge period. The adjustment unit 58 also saves the imaging delay time of 80 ms adjusted during the third adjustment of the imaging timing in the adjustment mode. Thereafter, the adjustment mode is switched to the detection mode (S1612), and the process proceeds to step S12 of the flowchart in FIG. 8.

[0085] As described above, each time the imaging timing is adjusted in the adjustment mode, the receiving member 28 may be rotated by the drive source 30. This allows the cleaning member 32 to wipe away droplets that have landed on the receiving surface 38 of the receiving member 28.

[0086] [1-3-2. Detection mode operation] The operation of the detection device 2 according to the first embodiment in the detection mode will be described with reference to Fig. 8, Fig. 14, and Fig. 15. Fig. 14 is a timing chart for explaining the operation of the detection device 2 according to the first embodiment in the detection mode. Fig. 15 is a diagram for explaining the operation of the detection device 2 according to the first embodiment in the detection mode.

[0087] Following the fourth adjustment of the imaging timing in the adjustment mode, the detection mode is executed as shown in Fig. 14. In the detection mode, steps S12 to S14 of the flowchart in Fig. 8 are executed. Next, in the detection mode (S15: "detection mode"), the presence or absence of droplet ejection defects is detected as follows (S17).

[0088] 14(a), after a discharge delay time of 250 ms has elapsed since the start of droplet discharge control by the discharge control unit 52, the discharge control unit 52 controls so that a predetermined amount of droplets is discharged from each of the discharge holes 12 of all (an example of a second number greater than the first number) of the nozzles 6. Also, as shown in Fig. 14(b), after a capture delay time of 80 ms, which was adjusted in the third adjustment of the capture timing in the adjustment mode, has elapsed since the start of image capture control by the image capture control unit 54, the image capture unit 36 ​​captures a plurality of subject images 46 at a predetermined frame rate.

[0089] As a result, in the detection mode, the imaging timing of the imaging unit 36 ​​is included in the above-mentioned ejection period, so that the droplet after landing is reflected in the second subject area 44 of the subject image 46 corresponding to the frame data with the frame number "frame 4," and the droplet in flight is reflected in the first subject area 42 of the subject image 46 corresponding to the frame data with the frame number "frame 3." The analysis unit 56 detects whether or not there is a defective ejection of the droplet by analyzing the subject image 46 corresponding to the frame data with the frame number "frame 3."

[0090] Here, with reference to (a) to (c) of Figure 15, we will explain an example of a method for analyzing the subject image 46 by the analysis unit 56 when controlling so that a predetermined amount of droplets are ejected from one ejection hole 12 of the nozzle 6.

[0091] First, as shown in (a) of FIG. 15, the analysis unit 56 extracts a difference image from the difference between the captured image and the background image. The captured image is a subject image 46 that shows droplets in flight discharged from one discharge hole 12 and the background, such as the receiver member 28. The background image is a subject image 46 that shows only the background, such as the receiver member 28. The difference image is an image that shows only droplets in flight discharged from one discharge hole 12. The background image is created in advance, for example, when the detection mode is started.

[0092] Next, as shown in FIG. 15(b), the analysis unit 56 binarizes the differential image extracted as described above.

[0093] 15(c), the analysis unit 56 calculates a black histogram in a vertical region in the binarized difference image corresponding to the position of one ejection hole 12 that ejected the droplets, and if the distribution amount of black is equal to or greater than a threshold, determines that droplets are present in the vertical region (i.e., the ejection of droplets from one ejection hole 12 is normal).On the other hand, if the distribution amount of black is less than the threshold, the analysis unit 56 determines that droplets are not present in the vertical region (i.e., the ejection amount of droplets from one ejection hole 12 is abnormal, or the flight direction of droplets from one ejection hole 12 is incorrect).

[0094] Next, with reference to FIG. 15(d), an example of a method for analyzing the subject image 46 by the analysis unit 56 when controlling so that a predetermined amount of droplets are discharged from all of the discharge holes 12 of the nozzle 6 will be described.

[0095] As shown in (d) of Fig. 15, the analysis unit 56 extracts a differential image in the same manner as described above, then binarizes the differential image and calculates a histogram of black color in each of a plurality of (e.g., seven) vertical regions corresponding to the positions of the plurality of ejection holes 12. In (d) of Fig. 15, the first to seventh vertical regions correspond to the positions of the first to seventh ejection holes 12, respectively. If the distribution amount of black color in each of the vertical regions is equal to or greater than a threshold, the analysis unit 56 determines that droplets are present in each of all vertical regions (i.e., the ejection of droplets from each of the plurality of ejection holes 12 is normal).

[0096] On the other hand, if the distribution amount of black in one or more vertical regions among the multiple vertical regions is less than the threshold value, the analysis unit 56 determines that no droplets are present in the one or more vertical regions (i.e., the ejection of droplets from one or more ejection holes 12 is abnormal). In the example shown in (d) of Fig. 15, the analysis unit 56 determines that the ejection of droplets from the fourth ejection hole 12 among the total of seven ejection holes 12 from the first to seventh ejection holes 12 is abnormal.

[0097] [1-4.Effects] As described above, in the detection device 2 of embodiment 1, in the adjustment mode, when a droplet is not captured in the first subject area 42 of each of a plurality of subject images 46 corresponding to a plurality of frame data, the imaging timing of the imaging unit 36 ​​is adjusted to a specific imaging timing so that a droplet is captured in the first subject area 42 of the subject image 46 corresponding to a specific frame data.

[0098] As a result, even when an imaging unit 36 ​​with a relatively low frame rate is used, the imaging timing of the imaging unit 36 ​​can be easily adjusted to a specific imaging timing in the adjustment mode, and the presence or absence of defective droplet ejection from the nozzle 6 can be accurately detected in the detection mode.

[0099] (Embodiment 2) A detection device 2A according to embodiment 2 will be described with reference to Fig. 16. Fig. 16 is a perspective view showing the internal structure of detection device 2A according to embodiment 2. In the following embodiments, the same components as those in embodiment 1 above are denoted by the same reference numerals, and their description will be omitted.

[0100] 16, in a detection mechanism 18A of a detection device 2A according to the second embodiment, a receiving surface 38 of a receiving member 28A is disposed substantially parallel to a horizontal plane (XY plane). In addition to the components described in the first embodiment, the detection device 2A also includes a flat mirror 60 for reflecting droplets that have landed on the receiving surface 38. The mirror 60 is disposed above the receiving surface 38 of the receiving member 28A and faces the imaging unit 36.

[0101] As a result, the imaging unit 36 ​​captures the droplets that have landed on the receiving surface 38 of the receiving member 28A, as reflected on the mirror 60, as the second subject area 44 of the subject image. In other words, the second subject area 44 is an area that includes the mirror 60, i.e., an area for capturing the droplets that have landed on the receiving surface 38 of the receiving member 28A through the mirror 60.

[0102] Therefore, even with a configuration such as that of the detection device 2A according to the second embodiment, it is possible to obtain the same effects as those of the first embodiment.

[0103] (Embodiment 3) A detection device 2B according to embodiment 3 will be described with reference to Fig. 17 and Fig. 18. Fig. 17 is a perspective view showing the appearance of the detection device 2B according to embodiment 3. Fig. 18 is a perspective view showing the appearance of the detection device 2B according to embodiment 3 with the cartridge 4 removed.

[0104] 17 and 18, the detection device 2B according to the third embodiment is a device for detecting whether or not there is a defect in the ejection of droplets from the nozzles (not shown) of the cartridge 4 detachably attached to the printing device 62. The detection mechanism (not shown) of the detection device 2B is configured in the same manner as the detection mechanism 18 of the first embodiment or the detection mechanism 18A of the second embodiment.

[0105] The printing device 62 is a handheld droplet ejection device that uses an inkjet system to eject a mist of ink (droplets) onto a recording medium to perform printing. The printing device 62 has a main body 64 and a lid 66. A recess 68 is formed on the top surface of the main body 64 for detachably mounting the cartridge 4. The lid 66 is rotatably supported on the top surface of the main body 64. The lid 66 is rotatable between a closed position (position shown in FIG. 17) in which it covers the recess 68 of the main body 64, and an open position (position shown in FIG. 18) in which it opens the recess 68 of the main body 64.

[0106] The container (not shown) of the cartridge 4 is filled with, for example, four types of ink, CMYK (C: cyan, M: magenta, Y: yellow, K: black).

[0107] Therefore, even with a configuration such as that of the detection device 2B according to the third embodiment, it is possible to obtain the same effects as those of the first embodiment.

[0108] (Variation) Although the detection devices according to the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0109] In each of the above embodiments, the adjustment unit 58 sets the imaging delay time to 2 times the reciprocal of the frame rate in the adjustment mode. nIn the above example, the imaging timing of the imaging unit 36 ​​is adjusted to a specific imaging timing by lengthening or shortening the imaging delay time by 1 / n (n is an integer greater than or equal to 1 and is the number of times the imaging timing has been adjusted), but this is not limiting. For example, in the adjustment mode, the adjustment unit 58 may adjust the imaging timing of the imaging unit 36 ​​to a specific imaging timing by shortening (or lengthening) the imaging delay time by a fixed time (an example of a predetermined time). In this case, if, as a result of the adjustment unit 58 shortening the imaging delay time by a fixed time, the frame number of the frame data in which the first droplet after landing in the current adjustment of the imaging timing is captured is greater than the frame number of the frame data in which the first droplet after landing in the initial adjustment of the imaging timing, the adjustment unit 58 may lengthen the imaging delay time by 1 / n (n is an integer greater than or equal to 2) of the fixed time.

[0110] Furthermore, in the above embodiment, the adjustment unit 58 adjusted the imaging timing of the imaging unit 36 ​​to a specific imaging timing by shortening or lengthening the imaging delay time so that the flying droplets are captured in the first subject area 42 of the subject image 46, but this is not limited to this, and the imaging timing of the imaging unit 36 ​​may also be adjusted to a specific imaging timing by, for example, adjusting the ejection time. [Industrial Applicability]

[0111] The present invention can be applied, for example, as a detection device for detecting whether or not there is a defect in the ejection of droplets from the nozzles of a cartridge. [Explanation of symbols]

[0112] 2, 2A, 2B Detector 4 cartridges 6 nozzles 8 Receiving section 10 Storage section 12 Discharge hole 14. Case 16 slots 18,18A Detection mechanism 20 Control board 22 Transmitter 24 Drive pulley 26 Driven pulley 28, 28A Receiving member 30 Power Source 32 Cleaning materials 34 Light source 36 Imaging unit 38 Receptive Surface 40 Flexible PCB 42 First subject area 44 Second Subject Area 46 Subject images 48 Memory section 50 control section 52 Discharge control section 54 Imaging control unit 56 Analysis Department 58 Adjustment part 60 Mirror 62 Printing device 64 Main body 66 Lid 68 Recess

Claims

1. A detection device for detecting whether or not there is a failure in ejecting droplets from a nozzle, comprising: a receiving member disposed opposite the nozzle and configured to receive droplets ejected from the nozzle; an imaging unit that images, as a single object image, a first object area for capturing an image of the droplets flying between the nozzle and the receiving member and a second object area for capturing an image of the droplets that have landed on the receiving member when the droplets are discharged from the nozzle toward the receiving member; a control unit for controlling the nozzle and the imaging unit, the control unit executing a first mode for adjusting an imaging timing of the imaging unit and a second mode for detecting the presence or absence of a discharge failure of droplets from the nozzle; The control unit is In the first mode, (i) droplets are ejected from the nozzles at a predetermined ejection timing, and the imaging unit is caused to capture the subject image at a predetermined frame rate; and (ii) when droplets are reflected in the second subject area of ​​the subject image corresponding to one or more frame data among the captured plurality of frame data, and droplets are not reflected in the first subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the imaging timing of the imaging unit is adjusted to a specific imaging timing so that droplets are reflected in the first subject area of ​​the subject image corresponding to a specific frame data among the plurality of frame data. In the second mode, (iii) droplets are ejected from the nozzle at the predetermined ejection timing, and the image capturing unit captures the subject image at the specific image capturing timing, and (iv) the presence or absence of a droplet ejection failure from the nozzle is detected based on the subject image captured at the specific image capturing timing. Detection device.

2. the nozzle has a plurality of ejection holes for ejecting droplets, In the first mode, the control unit causes droplets to be ejected from a first number of ejection holes among the plurality of ejection holes of the nozzle at the predetermined ejection timing, and in the second mode, causes droplets to be ejected from a second number of ejection holes, which is greater than the first number, among the plurality of ejection holes of the nozzle at the predetermined ejection timing. The detection device according to claim 1 .

3. The first number is one.

3. The detection device according to claim 2.

4. When droplets are ejected from the one ejection hole of the nozzle at the predetermined ejection timing in the first mode, if droplets are not reflected in either the first subject area or the second subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the control unit determines that one ejection hole has an ejection defect, changes the ejection hole that ejects droplets from the one ejection hole to another ejection hole, and executes the first mode again.

4. The detection device according to claim 3.

5. When, in the first mode, a liquid droplet is captured in the second subject area of ​​the subject image corresponding to one or more frame data among the plurality of frame data, and a liquid droplet is not captured in the first subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the control unit adjusts the imaging timing of the imaging unit to the specific imaging timing by lengthening or shortening an imaging delay time from the start of control of imaging by the imaging unit to the execution of imaging, by a predetermined time. The detection device according to any one of claims 1 to 4.

6. The predetermined time is 2 times the reciprocal of the frame rate. ｎ n is one part (n is an integer equal to or greater than 1) 6. The detection device according to claim 5.

7. the receiving member is an endless belt having a receiving surface that receives the droplets ejected from the nozzles, The detection device further comprises: A drive source for rotating the receiving member in a predetermined direction; a cleaning member that is arranged so as to come into contact with the receiving surface of the receiving member and that wipes off droplets that have landed on the receiving surface of the receiving member while the receiving member is rotating in the predetermined direction. The detection device according to claim 1 .

8. The detection device further includes a mirror for reflecting the droplets that have landed on the receiving member, The second object area is an area including the mirror. The detection device according to claim 1 .

9. A method for detecting whether or not a nozzle is failing to eject a droplet, comprising the steps of: (a) when droplets are discharged from the nozzle toward a receiving member disposed opposite the nozzle, capturing an image of a first subject area for capturing droplets flying between the nozzle and the receiving member and a second subject area for capturing droplets that have landed on the receiving member, as a single subject image, using an imaging unit; (b) executing a first mode of adjusting an image capturing timing of the image capturing unit; (c) executing a second mode for detecting whether or not there is a failure in ejecting droplets from the nozzle; In the first mode, (i) droplets are ejected from the nozzles at a predetermined ejection timing, and the subject image is captured by the imaging unit at a predetermined frame rate, and (ii) when droplets are reflected in the second subject area of ​​the subject image corresponding to one or more frame data among the captured plurality of frame data, and droplets are not reflected in the first subject area of ​​each of the plurality of subject images corresponding to the plurality of frame data, the imaging timing of the imaging unit is adjusted to a specific imaging timing so that droplets are reflected in the first subject area of ​​the subject image corresponding to a specific frame data among the plurality of frame data, In the second mode, (iii) droplets are discharged from the nozzle at the predetermined discharge timing, and the image of the subject is captured by the imaging unit at the specific image capturing timing, and (iv) the presence or absence of a discharge failure of the droplets from the nozzle is detected based on the image of the subject captured at the specific image capturing timing. Detection methods.

Images